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Organic & Biomolecular Chemistry
+
[M+Na] . Elemental analysis calcd. (%) for C H O (476.69): C
2
0-Iodo-icos-5-ene-7,9-diyne (3): (Scheme-6) MeLi-LiBr
32
44
3
complex (0.055 g, 0.508 mmol) in ether was added, under
nitrogen, to a THF (2 mL) solution of dec-5-ene-1,3-diynyl-
80.63, H 9.30, found: C 80.50, H 9.25.
20
trimethyl-silane 12 (0.080 g, 0.391 mmol) at room temperature. 60 Spectral data of minor isomer 20: [α]
- 11.64 (c 0.1,
D
5
After complete desilylation (2 h), the reaction mixture was cooled
to -80 °C and HMPA (0.176 g, 0.985 mmol) was added. A
solution of 1,10-diiododecane (0.154 g, 0.391 mmol) in THF (1
mL) was slowly dropped at the same temperature, then the
mixture was slowly brought to room temperature. After reaction
completion (12 h), the mixture was quenched with a saturated
aqueous solution of NaCl (5 mL), and extracted with ethyl acetate
CHCl ); R = 0.51 (petroleum ether : ethyl acetate 90:10); IR
3 f
-
1
(film): νmax (cm ) = (CHCl ): 3061, 2925, 2853, 1771, 1453,
3
1
1
361, 1170, 1105; H-NMR (300 MHz, CDCl ): δ 7.36-7.31 (m,
3
5
H, phenyl), 6.26 (dt, J = 7.02, 22.83 Hz, 1H 18CH), 5.36 (d, J =
6
5
15.81 Hz, 1H, 17CH), 4.59-4.57 (m, 2H, OCH Ph), 4.56-4.53 (m,
2
1
1
2
2
3
3
0
5
0
5
0
5
1
3
1
1
H, 24CH), 3.70 (dd, J = 3.63, 10.95 Hz, 1H, CHHOCH Ph),
2
.62 (dd, J = 5.25, 10.92 Hz, 1H, CHHOCH Ph), 2.71-2.68 (m,
2
(3 x 10 mL). The organic extracts were washed with a saturated
H, 2CH), 2.37-2.28 (m, 2H, 23CH ), 22.2 (t, J = 6.90 Hz, 2H,
2
aqueous saturated solution of NaCl (3 x 10 mL), dried over
anhydrous Na SO and concentrated under vacuum. The residue
2CH ), 2.09 (q, J = 7.02 Hz, 2H, 19CH ), 1.89-1.85 (m, 1H,
2
2
2
4
70 3CHH), 1.69 (m, 1H, 3CHH), 1.50-1.48 (m, 4H, 10CH , 11CH ),
2 2
was purified by column chromatography on silica gel (eluent:
petroleum ether) leading to the title compound 3 (0.139 g, 0.348
mmol, 89%).
1
0
1
1
.37 (m, 12H, aliphatic chain), 1.28 (brs, 4H, 20CH , 21CH ),
2 2
13
.86 (t, J = 6.90 Hz, 3H, 22CH3); C-NMR (75 MHz, CDCl ): δ
3
77.3 (C-1), 148.2 (C-18), 137.6 (C-phenyl), 128.4 (C-phenyl),
27.8 (C-phenyl), 127.6 (C-phenyl), 108.6 (C-17), 83.6 (C-13),
Compounds 19 & 20: Procedure: LDA (2 M soln in THF)
(0.500 mL,) was taken in dry THF (1.5 mL) at -40 °C. A solution
of the 5-Benzyloxymethyl-dihydro-furan-2-one 2 (0.031 g, 0.150
mmol) in THF (1 mL) was added and immediately the
temperature of the system was decreased to -78 °C. After
continuous stirring for 1 h at this temperature, 20-iodo-icos-5-
ene-7,9-diyne 3 (0.055 g, 0.150 mmol) in THF/DMPU (1:1, 1.5
mL) was slowly added. The reaction mixture was stirred for 12 h
at -15°C as the disappearance of the lactone was monitored by
TLC, and then terminated by adding aqueous HCl (1M, 8 mL).
After warming to room temperature, extracting the aqueous phase
7
8
8
9
5
0
5
0
78.9 (C-24), 77.2 (CH Ph), 74.04 (C-16), 73.5 (C-15), 71.5 (C-
2
2
2
5), 65.2 (C-14), 45.1 (C-2), 30.9 (C-3), 30.6 (C-20), 30.4 (C-19),
9.3 (C-23), 29.02 (C-5), 28.8 (C-6), 28.7 (C-7), 28.5 (C-8), 28.4
(
C-9), 28.2 (C-11), 26.8 (C-10), 24.1 (C-4), 22.1 (C-21), 19.5 (C-
2), 13.8 (C-22); MS (ESI, positive ion): m/z (%) = 499 (100)
1
+
[M+Na] . Elemental analysis calcd. (%) for C H O (476.69): C
32
44
3
8
0.63, H 9.30, found: C 80.55, H 9.28.
Compound (2S, 24S)-21 (major): To a stirred solution of the
major isomer (benzyl protected Debilisone ‛C’) 19 (0.017 g,
0.035 mmol) in DCM:H O (10:1, 1 mL), DDQ (0.012 g, 0.053
2
with Et O (3 x 10 mL), the combined organic extracts were dried
2
mmol, 1.5 equiv) was added and allowed to stir for overnight.
After completion of the reaction, it was filtered through celite.
The organic solvent was evaporated in vacuo to afford an oily
residue. The crude material was purified by column
chromatography on silica gel (eluent: 30 % ethyl acetate in
over anhydrous Na SO4 and the solvent was evaporated. The
2
residue was purified by column chromatography on silica gel
(eluent: 10 % ethyl acetate in petroleum ether) leading two
separable isomers 19 (major) and 20 (minor). Both are colourless
oil (major: 0.023 g, 0.050 mmol, 33.7%), (minor: 0.012 g, 0.025
mmol, 16.6%). CHN analyses were run on the separated isomers.
petroleum ether) to afford the alcohol 21 (0.012 g, 0.032 mmol,
20
9
3.94%) as a white amorphous solid. [α]
CHCl ); R = 0.45 (petroleum ether : ethyl acetate 1 : 9); IR
+ 52.1 (c 0.2,
D
2
0
Spectral data of major isomer 19: [α]
CHCl ); R = 0.53 (petroleum ether : ethyl acetate 90:10); IR
+ 43.25 (c 0.95,
D
3
f
-1
3
f
(
film): ν
(cm ) = (CHCl ): 3540, 2947, 2830, 2222, 1770,
max 3
-
1
(
film): νmax (cm ) = (CHCl ): 3061, 2915, 2843, 1765, 1451,
1
3
95
1469; H-NMR (300 MHz, CDCl ): δ 6.32 (dt, J = 7.1, 15.78 Hz,
3
1
4
4
5
5
0
5
0
5
1361, 1170; H-NMR (300 MHz, CDCl ): δ 7.37-7.30 (m, 5H,
3
1
2
4
2
H, 18CH), 5.50 (d, J = 15.81 Hz, 1H, 17CH), 4.58 (m, 1H,
4CH), 3.85 (dd, J = 2.82, 12.39 Hz, 1H, CHHOH), 3.62 (dd, J =
.59, 12.4 Hz, 1H, CHHOH), 2.684-2.681 (m, 1H, 2CH), 2.31-
.29 (m, 2H, 23CH ), 2.22 (t, J = 6.9 Hz, 2H, 12CH ); 2.09 (q, J
phenyl), 6.27 (dt, J = 7.02, 15.81 Hz, 1H 18CH), 5.49 (d, J =
1
2
3
5.81 Hz, 1H, 17CH), 4.63-4.60 (m, 1H, 24CH), 4.56-4.55 (m,
H, OCH Ph), 3.68 (dd, J = 3.54, 10.59 Hz, 1H, CHHOCH Ph),
2
2
2
2
.59 (dd, J = 3.9, 10.56 Hz, 1H, CHHOCH Ph), 2.71-2.62 (m,
2
1
1
1
00 = 7.02 Hz, 2H, 19CH ), 1.98-1.97 (m, 1H, 3CHH), 1.80 (m, 1H,
2
1H, 2CH), 2.31 (m, 2H, 23CH ), 22.2 (t, J = 6.84 Hz, 2H,
2
3
CHH), 1.54-1.49 (m, 4H, 10CH 11CH ), 1.42-1.29 (m, 12H,
2 2
1
3
1
0
2CH ), 2.09 (q, J = 7.02 Hz, 2H, 19CH ), 1.92-1.83 (m, 1H,
2 2
aliphatic chain), 1.28 (brs, 4H, 20CH , 21CH ), 0.87 (t, J = 6.9
2
2
CHH), 1.72 (m, 1H, 3CHH), 1.52 (m, 4H, 10CH , 11CH ), 1.40-
2
13
Hz, 3H, 22CH3); C-NMR (75 MHz, CDCl ): δ 177.7 (C-1),
2
3
.30 (m, 12H, aliphatic chain), 1.28 (brs, 4H, 20CH , 21CH ),
2
2
1
48.8 (C-18), 108.5 (C-17), 83.8 (C-13), 78.7 (C-24), 74.0 (C-
1
3
.86 (t, J = 6.93 Hz, 3H, 22CH3); C-NMR (75 MHz, CDCl ): δ
3
05 16), 72.8 (C-15), 65.8 (C-25), 64.9 (C-14), 40.0 (C-2), 31.2 (C-3),
177.3 (C-1), 148.2 (C-18), 137.6 (C-phenyl), 128.4 (C-phenyl),
3
2
0.6 (C-20), 30.48 (C-19), 30.45 (C-5), 29.3 (C-23), 29.1 (C-6),
8.82 (C-7), 28.81 (C-8), 28.7 (C-9), 28.4 (C-10), 28.2 (C-11),
1
7
2
2
27.8 (C-phenyl), 127.6 (C-phenyl), 108.6 (C-17), 83.6 (C-13),
8.9 (C-24), 77.2 (CH Ph), 74.05 (C-16), 73.5 (C-15), 71.5 (C-
2
27.2 (C-4), 22.2 (C-21), 19.5 (C-12), 13.6 (C-22); MS (ESI,
+
positive ion): m/z (%) = 409 (100) [M+Na] . Elemental analysis
5), 65.2 (C-14), 45.1 (C-2), 30.9 (C-3), 30.6 (C-20), 30.4 (C-19),
9.3 (C-23), 29.01 (C-5), 28.8 (C-6), 28.7 (C-7), 28.5 (C-8), 28.4
10 calcd. (%) for C H O (386.57): C 77.68, H 9.91, found: C
38
25
3
(C-9), 28.2 (C-11), 26.8 (C-10), 24.1 (C-4), 22.1 (C-21), 19.5 (C-
2), 13.8 (C-22); MS (ESI, positive ion): m/z (%) = 499 (100)
7
7.61, H 9.87.
1
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